Got the Looks but Not the Charm

Simgha was a rather handsome young man. He lived with his aging parents. He was not too great with women.

If we had lived in his time and vicinity you would have said of him,
He's got the looks and the build but not the charm.

Wasn't it Shania Twain? Who sang
Oh you're Brad Pitt? - That don't impress me much.

I can't help but keep wondering why country singers frequently use the plural don't in place of the singular doesn't.